C4.2. Transfers of energy and matter

Distinguish between the transfers of energy and inorganic nutrients in ecosystems.

The diagram shows the food web for an aquatic ecosystem in which letters R–Z represent individual species.

[Source: © International Baccalaureate Organization 2019]

Which organism is a tertiary consumer?

A. Organism T

B. Organism U

C. Organism W

D. Organism Y

Explain the reasons for food chains rarely containing more than four or five trophic levels.

The diagram shows the food web for an aquatic ecosystem in which letters R–Z represent individual species.

[Source: © International Baccalaureate Organization 2019]

Which organism is a tertiary consumer?

A. Organism T

B. Organism U

C. Organism W

D. Organism Y

Outline energy flow through a community in a natural ecosystem.

Outline how energy flows in an ecosystem.

The Silver Springs feed into the Silver River in Florida. The diagram shows a pyramid of energy for the Silver Springs ecosystem. The units are kJ m^–2 y^–1.

[Source: © International Baccalaureate Organization 2019]

What do level I and level III represent in the pyramid of energy?

Distinguish between the transfers of energy and inorganic nutrients in ecosystems.

Distinguish between the transfers of energy and inorganic nutrients in ecosystems.

The diagram shows the food web for an aquatic ecosystem in which letters R–Z represent individual species.

[Source: © International Baccalaureate Organization 2019]

Which organism is a tertiary consumer?

A. Organism T

B. Organism U

C. Organism W

D. Organism Y

Explain the reasons for food chains rarely containing more than four or five trophic levels.

Explain the reasons for food chains rarely containing more than four or five trophic levels.

The diagram shows the food web for an aquatic ecosystem in which letters R–Z represent individual species.

[Source: © International Baccalaureate Organization 2019]

Which organism is a tertiary consumer?

A. Organism T

B. Organism U

C. Organism W

D. Organism Y

Outline energy flow through a community in a natural ecosystem.

Outline energy flow through a community in a natural ecosystem.

Outline how energy flows in an ecosystem.

Outline how energy flows in an ecosystem.

The Silver Springs feed into the Silver River in Florida. The diagram shows a pyramid of energy for the Silver Springs ecosystem. The units are kJ m^–2 y^–1.

[Source: © International Baccalaureate Organization 2019]

What do level I and level III represent in the pyramid of energy?

The image shows an example of a soil food web.

[Source: Anon., n.d. The Soil Food Web. [image online] Available at: https://www.nrcs.usda.gov/wps/portal/nrcs/
photogallery/soils/health/biology/gallery/?cid=1788&position=Promo [Accessed 11 March 2020].]

Draw a food chain from this food web, showing at least three organisms.

Models are used as representations of the real world. Evaluate the use of food webs to represent ecological communities.

Humans have persecuted predators such as coyotes (Canis latrans), causing severe reduction in the number of large carnivores throughout the world. The diagram represents part of a food web in Texas, USA.

_{[Source: Coyote: https://commons.wikimedia.org/wiki/File:2009-Coyote-Yosemite.jpg. CC-BY-SA 3.0; Yathin S. Krishnappa, Jan.
2009, Coyote from Yosemite National Park, California in snow.]
[Source: Fox: https://commons.wikimedia.org/wiki/File:Foxes_of_Island_Beach_State_Park_New_Jersey_(16324545492).jpg.
CC-Attribution 2.0; Anthony Quintano, Jan. 2015, Foxes of Island Beach State Park New Jersey.]
[Source: Rodent/Brown Rat: https://commons.wikimedia.org/wiki/File:Rattus_norvegicus_-_Brown_rat_02.jpg. CC-BY-SA-4.0
Zeynel Cebeci, May 2020; Brown Rat, Adana, Turkey.]
[Source: Lagomorph: https://commons.wikimedia.org/wiki/File:Eastern_Cottontail.JPG. CC 3.0. Taken by Gareth Rasberry,
Huntington Beach State Park, Murrells Inlet, South Carolina, USA.]
[Source: Nest Eggs: https://commons.wikimedia.org/wiki/File:Eastern_Phoebe-nest-Brown-headed-Cowbird-egg.jpg. CC 3.0.
Galawebdesign, June 2007, Eastern Phoebe (Sayornis phoebe) nest with one Brown-headed Cowbird (Molothrus ater)
egg.]}

What is a possible outcome for the lagomorph population in this ecosystem if coyote numbers were controlled by killing them to reduce losses of domestic livestock?

A.  Decrease because there are fewer predators

B.  Increase because there are fewer foxes to eat them

C.  Decrease because there are more rodents for foxes to eat

D.  Increase because, although there are more foxes, there are also more rodents

The image shows an example of a soil food web.

[Source: Anon., n.d. The Soil Food Web. [image online] Available at: https://www.nrcs.usda.gov/wps/portal/nrcs/
photogallery/soils/health/biology/gallery/?cid=1788&position=Promo [Accessed 11 March 2020].]

Draw a food chain from this food web, showing at least three organisms.

The image shows an example of a soil food web.

[Source: Anon., n.d. The Soil Food Web. [image online] Available at: https://www.nrcs.usda.gov/wps/portal/nrcs/
photogallery/soils/health/biology/gallery/?cid=1788&position=Promo [Accessed 11 March 2020].]

Draw a food chain from this food web, showing at least three organisms.

Models are used as representations of the real world. Evaluate the use of food webs to represent ecological communities.

Humans have persecuted predators such as coyotes (Canis latrans), causing severe reduction in the number of large carnivores throughout the world. The diagram represents part of a food web in Texas, USA.

_{[Source: Coyote: https://commons.wikimedia.org/wiki/File:2009-Coyote-Yosemite.jpg. CC-BY-SA 3.0; Yathin S. Krishnappa, Jan.
2009, Coyote from Yosemite National Park, California in snow.]
[Source: Fox: https://commons.wikimedia.org/wiki/File:Foxes_of_Island_Beach_State_Park_New_Jersey_(16324545492).jpg.
CC-Attribution 2.0; Anthony Quintano, Jan. 2015, Foxes of Island Beach State Park New Jersey.]
[Source: Rodent/Brown Rat: https://commons.wikimedia.org/wiki/File:Rattus_norvegicus_-_Brown_rat_02.jpg. CC-BY-SA-4.0
Zeynel Cebeci, May 2020; Brown Rat, Adana, Turkey.]
[Source: Lagomorph: https://commons.wikimedia.org/wiki/File:Eastern_Cottontail.JPG. CC 3.0. Taken by Gareth Rasberry,
Huntington Beach State Park, Murrells Inlet, South Carolina, USA.]
[Source: Nest Eggs: https://commons.wikimedia.org/wiki/File:Eastern_Phoebe-nest-Brown-headed-Cowbird-egg.jpg. CC 3.0.
Galawebdesign, June 2007, Eastern Phoebe (Sayornis phoebe) nest with one Brown-headed Cowbird (Molothrus ater)
egg.]}

What is a possible outcome for the lagomorph population in this ecosystem if coyote numbers were controlled by killing them to reduce losses of domestic livestock?

A.  Decrease because there are fewer predators

B.  Increase because there are fewer foxes to eat them

C.  Decrease because there are more rodents for foxes to eat

D.  Increase because, although there are more foxes, there are also more rodents

Describe how autotrophs absorb light energy

Describe how autotrophs absorb light energy

Describe how autotrophs absorb light energy

Describe how autotrophs absorb light energy

Describe how autotrophs absorb light energy

Describe how autotrophs absorb light energy

Explain what information is needed to find the trophic level of pangolins.

Explain what information is needed to find the trophic level of pangolins.

Identify the trophic level of sea lions. [

Explain what information is needed to find the trophic level of pangolins.

Explain what information is needed to find the trophic level of pangolins.

Explain what information is needed to find the trophic level of pangolins.

Explain what information is needed to find the trophic level of pangolins.

Identify the trophic level of sea lions. [

A pyramid of energy represents the amount of energy taken in by each trophic level per unit time and per unit area. Discuss the advantages and disadvantages of the use of pyramids of energy as models of energy flow in an ecosystem.

Explain what information a pyramid of energy provides about an ecological community.

The diagram shows the flow of energy through an ecosystem in ${\text{kJ\hspace{0.05em}m}}^{–2}{\text{\hspace{0.05em}y}}^{–1}.$

A pyramid of energy represents the amount of energy taken in by each trophic level per unit time and per unit area. Discuss the advantages and disadvantages of the use of pyramids of energy as models of energy flow in an ecosystem.

Explain what information a pyramid of energy provides about an ecological community.

The diagram shows the flow of energy through an ecosystem in ${\text{kJ\hspace{0.05em}m}}^{–2}{\text{\hspace{0.05em}y}}^{–1}.$

Outline energy flow through a community in a natural ecosystem.

Outline energy flow through a community in a natural ecosystem.

Outline energy flow through a community in a natural ecosystem.

State two causes of the decrease of biomass along food chains in terrestrial ecosystems.

Suggest a reason that the mass of protein and lipid mixture eaten at 25:1 is lower than at 50:1.

State two causes of the decrease of biomass along food chains in terrestrial ecosystems.

State two causes of the decrease of biomass along food chains in terrestrial ecosystems.

Suggest a reason that the mass of protein and lipid mixture eaten at 25:1 is lower than at 50:1.

Suggest a reason that the mass of protein and lipid mixture eaten at 25:1 is lower than at 50:1.

State the mean annual decline in insect biomass.

Calculate the number of Coleoptera species that would be expected to exist after one year from a starting number of 400$$000 species, assuming the mean rate of decline.

Compare and contrast the results for the 1:1 and the 1:10 P:L diets.

Suggest a reason that the mass of protein and lipid mixture eaten at 25:1 is lower than at 50:1.

Suggest with a reason which P:L diet is closest to the normal diet of these bumblebees.

State the mean annual decline in insect biomass.

Calculate the number of Coleoptera species that would be expected to exist after one year from a starting number of 400$$000 species, assuming the mean rate of decline.

Compare and contrast the results for the 1:1 and the 1:10 P:L diets.

Suggest a reason that the mass of protein and lipid mixture eaten at 25:1 is lower than at 50:1.

Suggest with a reason which P:L diet is closest to the normal diet of these bumblebees.

State the mean annual decline in insect biomass.

Calculate the number of Coleoptera species that would be expected to exist after one year from a starting number of 400$$000 species, assuming the mean rate of decline.

Compare and contrast the results for the 1:1 and the 1:10 P:L diets.

Suggest a reason that the mass of protein and lipid mixture eaten at 25:1 is lower than at 50:1.

Suggest with a reason which P:L diet is closest to the normal diet of these bumblebees.

State the mean annual decline in insect biomass.

Calculate the number of Coleoptera species that would be expected to exist after one year from a starting number of 400$$000 species, assuming the mean rate of decline.

Compare and contrast the results for the 1:1 and the 1:10 P:L diets.

Suggest with a reason which P:L diet is closest to the normal diet of these bumblebees.

State the mean annual decline in insect biomass.

Calculate the number of Coleoptera species that would be expected to exist after one year from a starting number of 400$$000 species, assuming the mean rate of decline.

Compare and contrast the results for the 1:1 and the 1:10 P:L diets.

Suggest with a reason which P:L diet is closest to the normal diet of these bumblebees.

State the mean annual decline in insect biomass.

Calculate the number of Coleoptera species that would be expected to exist after one year from a starting number of 400$$000 species, assuming the mean rate of decline.

Compare and contrast the results for the 1:1 and the 1:10 P:L diets.

Suggest with a reason which P:L diet is closest to the normal diet of these bumblebees.

State one process that results in the loss of carbon dioxide from a marine organism such as a crustacean or a jellyfish.

The crustacean and the jellyfish obtain carbon compounds by feeding. State one source of carbon for marine organisms, other than feeding.

In the diagram, which of the processes labelled A to D transfers the largest mass of carbon per year in a woodland ecosystem?

[Source: © International Baccalaureate Organization 2019]

The diagram shows the carbon flux in gigatonnes per year between some of the Earth’s global reservoirs.

[Source: Figure 7.3 and Table 7.1 from Denman, K.L., G. Brasseur, A. Chidthaisong, P. Ciais, P.M. Cox, R.E. Dickinson, D.
Hauglustaine, C. Heinze, E. Holland, D. Jacob, U. Lohmann, S Ramachandran, P.L. da Silva Dias, S.C. Wofsy and
X. Zhang, 2007: Couplings Between Changes in the Climate System and Biogeochemistry. In: Climate Change
2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the
Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt,
M. Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.]

What can be deduced from the information in the diagram?

A. Arrows S are mainly due to respiration of marine plants and animals.

B. Photosynthesis is a component of both arrows Q and S.

C. Every day, more carbon is removed from the ocean than is added.

D. Ocean carbon is stored as dissolved calcium carbonate.

The diagram shows part of the carbon cycle involving methane.

[Source: NASA GISS, n.d. Rough schematic of methane sources and sinks. [diagram online] Available at:
https://www.giss.nasa.gov/research/features/200409_methane/ [Accessed 26 October 2021].]

Which conditions favour methane production in W, X and Y?

A.  Presence of eubacteria and organic matter

B.  Presence of archaeans and waterlogged soil

C.  Presence of eubacteria and waterlogged soil

D.  Presence of archaeans and oxygen

Outline the stages of the carbon cycle that involve plants or materials made by plants.

Describe processes in the carbon cycle that produce or use carbon dioxide.

State one process that results in the loss of carbon dioxide from a marine organism such as a crustacean or a jellyfish.

The crustacean and the jellyfish obtain carbon compounds by feeding. State one source of carbon for marine organisms, other than feeding.

State one process that results in the loss of carbon dioxide from a marine organism such as a crustacean or a jellyfish.

The crustacean and the jellyfish obtain carbon compounds by feeding. State one source of carbon for marine organisms, other than feeding.

In the diagram, which of the processes labelled A to D transfers the largest mass of carbon per year in a woodland ecosystem?

[Source: © International Baccalaureate Organization 2019]

The diagram shows the carbon flux in gigatonnes per year between some of the Earth’s global reservoirs.

[Source: Figure 7.3 and Table 7.1 from Denman, K.L., G. Brasseur, A. Chidthaisong, P. Ciais, P.M. Cox, R.E. Dickinson, D.
Hauglustaine, C. Heinze, E. Holland, D. Jacob, U. Lohmann, S Ramachandran, P.L. da Silva Dias, S.C. Wofsy and
X. Zhang, 2007: Couplings Between Changes in the Climate System and Biogeochemistry. In: Climate Change
2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the
Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt,
M. Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.]

What can be deduced from the information in the diagram?

A. Arrows S are mainly due to respiration of marine plants and animals.

B. Photosynthesis is a component of both arrows Q and S.

C. Every day, more carbon is removed from the ocean than is added.

D. Ocean carbon is stored as dissolved calcium carbonate.

The diagram shows part of the carbon cycle involving methane.

[Source: NASA GISS, n.d. Rough schematic of methane sources and sinks. [diagram online] Available at:
https://www.giss.nasa.gov/research/features/200409_methane/ [Accessed 26 October 2021].]

Which conditions favour methane production in W, X and Y?

A.  Presence of eubacteria and organic matter

B.  Presence of archaeans and waterlogged soil

C.  Presence of eubacteria and waterlogged soil

D.  Presence of archaeans and oxygen

Outline the stages of the carbon cycle that involve plants or materials made by plants.

Outline the stages of the carbon cycle that involve plants or materials made by plants.

Describe processes in the carbon cycle that produce or use carbon dioxide.

Describe processes in the carbon cycle that produce or use carbon dioxide.

State one process that results in the loss of carbon dioxide from a marine organism such as a crustacean or a jellyfish.

The crustacean and the jellyfish obtain carbon compounds by feeding. State one source of carbon for marine organisms, other than feeding.

In the diagram, which of the processes labelled A to D transfers the largest mass of carbon per year in a woodland ecosystem?

[Source: © International Baccalaureate Organization 2019]

The table shows the global carbon budget over two decades; the years 1990 to 1999 and 2000 to 2009.

[Source: © International Baccalaureate Organization 2019]

Using the table, explain causes of the changes in carbon flux over the two decades.

The diagram shows the carbon flux in gigatonnes per year between some of the Earth’s global reservoirs.

[Source: Figure 7.3 and Table 7.1 from Denman, K.L., G. Brasseur, A. Chidthaisong, P. Ciais, P.M. Cox, R.E. Dickinson, D.
Hauglustaine, C. Heinze, E. Holland, D. Jacob, U. Lohmann, S Ramachandran, P.L. da Silva Dias, S.C. Wofsy and
X. Zhang, 2007: Couplings Between Changes in the Climate System and Biogeochemistry. In: Climate Change
2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the
Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt,
M. Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.]

What can be deduced from the information in the diagram?

A. Arrows S are mainly due to respiration of marine plants and animals.

B. Photosynthesis is a component of both arrows Q and S.

C. Every day, more carbon is removed from the ocean than is added.

D. Ocean carbon is stored as dissolved calcium carbonate.

Explain the transformations of carbon compounds in the carbon cycle.

Describe how plants affect the amount of carbon dioxide in the atmosphere.

Carbon sinks are any reservoirs that absorb and store carbon dioxide from the atmosphere. Which process increases the size of the carbon sink in oceans?

A.  Photosynthesis

B.  Respiration

C.  Ocean acidification

D.  Decomposition

State one process that results in the loss of carbon dioxide from a marine organism such as a crustacean or a jellyfish.

The crustacean and the jellyfish obtain carbon compounds by feeding. State one source of carbon for marine organisms, other than feeding.

State one process that results in the loss of carbon dioxide from a marine organism such as a crustacean or a jellyfish.

The crustacean and the jellyfish obtain carbon compounds by feeding. State one source of carbon for marine organisms, other than feeding.

In the diagram, which of the processes labelled A to D transfers the largest mass of carbon per year in a woodland ecosystem?

[Source: © International Baccalaureate Organization 2019]

The table shows the global carbon budget over two decades; the years 1990 to 1999 and 2000 to 2009.

[Source: © International Baccalaureate Organization 2019]

Using the table, explain causes of the changes in carbon flux over the two decades.

The table shows the global carbon budget over two decades; the years 1990 to 1999 and 2000 to 2009.

[Source: © International Baccalaureate Organization 2019]

Using the table, explain causes of the changes in carbon flux over the two decades.

The diagram shows the carbon flux in gigatonnes per year between some of the Earth’s global reservoirs.

[Source: Figure 7.3 and Table 7.1 from Denman, K.L., G. Brasseur, A. Chidthaisong, P. Ciais, P.M. Cox, R.E. Dickinson, D.
Hauglustaine, C. Heinze, E. Holland, D. Jacob, U. Lohmann, S Ramachandran, P.L. da Silva Dias, S.C. Wofsy and
X. Zhang, 2007: Couplings Between Changes in the Climate System and Biogeochemistry. In: Climate Change
2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the
Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt,
M. Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.]

What can be deduced from the information in the diagram?

A. Arrows S are mainly due to respiration of marine plants and animals.

B. Photosynthesis is a component of both arrows Q and S.

C. Every day, more carbon is removed from the ocean than is added.

D. Ocean carbon is stored as dissolved calcium carbonate.

Explain the transformations of carbon compounds in the carbon cycle.

Explain the transformations of carbon compounds in the carbon cycle.

Describe how plants affect the amount of carbon dioxide in the atmosphere.

Describe how plants affect the amount of carbon dioxide in the atmosphere.

Carbon sinks are any reservoirs that absorb and store carbon dioxide from the atmosphere. Which process increases the size of the carbon sink in oceans?

A.  Photosynthesis

B.  Respiration

C.  Ocean acidification

D.  Decomposition

In the diagram, which of the processes labelled A to D transfers the largest mass of carbon per year in a woodland ecosystem?

[Source: © International Baccalaureate Organization 2019]

Calculate the percentage increase in the use of liquid fuels from 1950 to 1975.

%

Referring to the data, compare and contrast the changes in the use of the different fuels between 1950 and 1975.

Describe how plants affect the amount of carbon dioxide in the atmosphere.

Carbon sinks are any reservoirs that absorb and store carbon dioxide from the atmosphere. Which process increases the size of the carbon sink in oceans?

A.  Photosynthesis

B.  Respiration

C.  Ocean acidification

D.  Decomposition

Describe processes in the carbon cycle that produce or use carbon dioxide.

In the diagram, which of the processes labelled A to D transfers the largest mass of carbon per year in a woodland ecosystem?

[Source: © International Baccalaureate Organization 2019]

Calculate the percentage increase in the use of liquid fuels from 1950 to 1975.

%

Referring to the data, compare and contrast the changes in the use of the different fuels between 1950 and 1975.

Describe how plants affect the amount of carbon dioxide in the atmosphere.

Describe how plants affect the amount of carbon dioxide in the atmosphere.

Carbon sinks are any reservoirs that absorb and store carbon dioxide from the atmosphere. Which process increases the size of the carbon sink in oceans?

A.  Photosynthesis

B.  Respiration

C.  Ocean acidification

D.  Decomposition

Describe processes in the carbon cycle that produce or use carbon dioxide.

Describe processes in the carbon cycle that produce or use carbon dioxide.

Distinguish between the transfers of energy and inorganic nutrients in ecosystems.

Explain the transformations of carbon compounds in the carbon cycle.

Distinguish between the transfers of energy and inorganic nutrients in ecosystems.

Distinguish between the transfers of energy and inorganic nutrients in ecosystems.

Explain the transformations of carbon compounds in the carbon cycle.

Explain the transformations of carbon compounds in the carbon cycle.